1. Field of the Invention
This invention relates to an improved flashing system for cavity wall structures. More specifically the invention relates to channeled flashings having protected channels, which channels are protected from being clogged by mortar and construction debris. The flashings are designed for mounting with an open end of the channel in communication with the exterior of the cavity wall and the protected channel in the cavity to enable the channel to operate as a conduit between the cavity and the exterior.
2. Description of the Prior Art
In the past, investigations relating to cavity wall flashing systems for brick veneer masonry construction have been conducted. While strides have been made in flashing-related technologies, including metal foils, polymeric and elastomeric materials and hot melt adhesives, there still remain several areas where continued development is ongoing. The inventors' patents and their assignee's product line are all related to accessories for cavity wall structures and include masonry flashing, insulation, and anchoring and seismic devices, and are sold under the trademarks of Seismiclip®, Byna-Tie®, and DW-10-X®, X-Seal®, Foam Tech®, and FlexFlash™. These products, which are manufactured by Hohmann & Barnard, Inc., Hauppauge, N.Y. 11788, have become widely accepted in the construction industry and have provided the inventors with particular insight into the technological needs of this marketplace.
Masonry walls with brick veneer are designed with an inner and an outer wythe and a cavity therebetween. The backup wall or inner wythe and insulation thereon isolates the interior of the building from the environment, and the brick veneer outer wythe provides an aesthetic finish to the building and a system of weep holes for removing fluids from the cavity. The inner wythe is constructed to exclude water and water vapor from the interior. Where excessive levels of water or water vapor are present in the cavity, the deterioration of building materials is hastened. Various masonry flashing systems in the past have been adopted to function cooperatively with the system of weep holes.
In the past, protective systems have been devised to prevent the blockage of weep holes by excess mortar and construction debris which fall into the cavity during construction. Of note in this regard is the MORTAR NET system developed by Tom Sourlis and described in U.S. Pat. Nos. 5,230,189, RE.36,676, and 6,023,892. Other examples of such systems provided by U.S. Pat. No. 6,684,579 B2 issued to Brunson et al.; U.S. Pat. No. 5,692,348 issued to Ambrosino; U.S. Pat. No. 6,256,955 issued to Lolley; U.S. Pat. No. 5,598,673 issued to Atkins; and, U.S. Pat. No. 5,860,259 issued to Laska. More recently systems have been described in U.S. Patent Applications 2004/0003558 A1 and 2003/0230035 A1 of Collins et al. and U.S. Patent Application 2006/0117687 of Ehrman et al.
Because of widespread usage and familiarity with bituminous and asphaltic products in roofing applications, when masonry flashing systems were first designed, the building construction industry adopted the familiar copper and asphalt products. At that time the technology of pressure-sensitive hot melt adhesives needed for peel-and-stick applications was insufficiently developed. Some critics indicated that the tackiness of the non-asphaltic products was insufficient for the rough masonry block surfaces.
Because of the presence of plasticizers, others were apprehensive about the available hot melt adhesives meeting the requisite fire retardancy standards. Also, to provide fire retardancy, some pressure-sensitive products were marketed for building construction use with inorganic fillers, such as alumina trihydrate, antimony oxide or calcium carbonate. However, these filled pressure-sensitive products had disadvantages, such as application problems, phase separation, toxicity, and reduced adhesion upon activation.
The inventors hereof have in inventions related hereto made improvements in the masonry flashing art. Hohmann et al. U.S. Pat. Nos. 6,584,746 issued Jul. 1, 2003; 6,928,780 issued Aug. 16, 2005; and, 6,945,000 issued Sep. 10, 2005 provide masonry flashing systems which are suitable either for surface-mounting with a termination bar or for through-wall mounting. The devices use state-of-the-art adhesives and various flashing membranes and composites.
A published patent application, namely, U.S. Patent Application 2005/0028455 of Koch et al. describes a combination flashing and drainage system. The system described uses a layer of polypropylene or equivalent as a wicking material to transport water. As wicks are hydrophilic, water is moved from wetter to drier areas of the wick and are reversible. The Koch et al. system relies on evaporation at the outer exterior edge thereof to reduce the total water content.
In preparing for this application the below-mentioned patents, some of which are discussed above, came to the attention of the inventors. The other patents are believed to be relevant to the further discussion of the prior art, which follows:
PatentInventorIssue Date6,945,000Hohmann et al.Sep. 20, 20056,928,780Hohmann et al.Aug. 16, 20056,684,579Branson et al.6,584,746Hohmann et al.Jul. 1, 20036,256,955Lolley6,224,700OakleyMay 1, 20016,035,582PacificMar. 14, 20005,870,864SnyderFeb. 16, 19995,860,259LaskaJan. 19, 19995,692,348Ambrosino5,598,673Atkins4,910,931PardueMar. 27, 19904,775,567HarknessOct. 4, 19884,755,409HarknessJul. 5, 19884,295,911Haage et al.Oct. 20, 19814,239,795Haage et al.Dec. 16, 1980